Abstract
The pharmacology of the cyclic ADP-ribose (cADPR)-dependent Ca+2 release mechanism is very similar to that of the ryanodine receptor (RyR). Here we showed that MgCl2, a known inhibitor of RyR, blocked cADPR-induced Ca+2 release in sea urchin egg homogenates with a half maximal concentration of about 2.5 mM. The effect was specific since up to 10 mM Mg+2 had no effect on the Ca+2 release induced by inositol trisphosphate. K2ATP, another known modulator of RyR, at up to 10 mM did not affect the half-maximal concentration of cADPR, which remained at about 96 nM. These results indicate cADPR is a specific Ca+2 release activator and not merely an adenine nucleotide acting on the ATP-site. The inhibitory effects of Mg+2 further demonstrate the similarity between RyR and the cADPR-dependent Ca+2 release system.
Original language | English (US) |
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Pages (from-to) | 786-791 |
Number of pages | 6 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 206 |
Issue number | 2 |
DOIs | |
State | Published - Jan 1 1995 |